Direct Membership rule parameters

[ebonyknight]

We are investigating SMS 2.0 and doing some collections. The default collection is "All systems", but not all our machines are showing up (NT clients). We found the Create Direct Membership Rule Wizard, but can't find any explainations to the parameters listed in the Resource Class field and the Attribute Name field. I have the SMS 2.0 Admin Companion, but those entries aren't explained.

I am aware of the NT systems collection, but wanted to find explanations to the fields.

Also, is there a way when creating a package to change the default from All systems to something else? I know I can pick the one I want from the drop down list, but can I change it so that a particular collection is the default other than All systems?

Thanks.